Tiffany reported third-quarter comparable sales that fell short of Wall Street estimates as spending by Chinese tourists slowed in some regions. Full-year earnings guidance also fell short. Shares plunged more than 11. The high-end jeweler said total comparabale sales, excluding foreign-exchange fluctuations, rose 3 in the third quarter, missing the 5.6 gain that analysts surveyed by Bloomberg were expecting. It reported earnings of $0.77 a share on revenue of $1.01 billion, missing the $0.78 and $1.05 billion that analysts were hoping for.